miRNome sequencing of muscle specimens and cultures from spinal muscular atrophy (SMA) patients

Spinal muscular atrophy (SMA) is a neuromuscular disorder characterized by second motor-neuron degeneration, ranging from severe to mild forms. Irrespective of the severity, all patients have a homozygous loss of the SMN1 gene. SMN2 is a hypomorphic allele, producing insufficient protein levels, due to the alternative splicing of exon 7. SMN2 copy number is variable in patients (two-to-four) and grossly related to disease severity. Besides the SMN2 products, few SMN-independent biomarkers have been evaluated so far. In this scenario, the main goal of this study was the identification of candidate microRNAs useful as biomarkers for SMA, which can be objectively evaluated in patients and that could be related to the severity of the disease. In this regard, we performed a miRNome analysis in myoblasts, myotubes, and biopsies derived from SMA patients. The miRNome profiling performed in muscular SMA human samples can give not only the possibility to identify miRNAs as easily measurable biomarkers but also investigate their putative role in muscular maturation defect in SMA patients.